Thermal cut-out device.



No. 800,820. PATBNTED OCT. 3, 1905. 0. A. ROLFE.

THERMAL CUT-OUT DEVICE.

APPLICATION FILED JAN.11. 1897. RENEWED JULY 27,1904.

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UNITED sTA s PATENT OFFICE.

CHARLES A. ROLFE, OF ADRIAN, MICHIGAN, ASSIGNOR, BY MESNE ASSIGNMENTS, TO ROLFE ELECTRIC CO., OF ROCHESTER, NEIV YORK, A CORPORATION OF NEIV YORK.

THERMAL CUT-OUT DEVICE.

Specification of Letters Patent.

Patented Oct. 3, 1905.

Application filed January 11, 1897. Renewed July 2'7, 1904:. Serial No. 218,308-

To all whom, it may concern:

Be it known that I, CnARLEs A. RoLEE, a citizen of the United States, residing at Adrian, in the county of Lenawee and State of Michigan, have invented a certain new and useful Improvement in Thermal Cut-Out Devices, of which the following is a full, clear, concise, and exact description, reference being had to the accompanying drawings, forming a part of this specification.

My invention relates to electrical-circuit protectors for automatically opening or b reaking low-tension circuits on the intrusion thereon of unduly-strong currents, such as emanate from electric light and power circuits.

Prominent objects of the invention are to provide a simple, practical, and effective device of this kind; to permit the same to be assembled with case, so that a large number of devices can be arranged in a comparatively small space; to insure easy and accurate operation of the device, and to accomplish the above results in a practical and expeditious manner.

In the accompanying drawings, Figure 1 is a plan view of an electric-oircuit-protective apparatus embodying my present invention. Fig. 2 is a section taken on line a w in Fig. 1. Fig. 3 is a plan view of a modified form of device.

In the drawings, C is a base which may be of suitable insulating material, such as rubber, ebonite, porcelain, or the like. This base can be a part of a large board or structure capable of accommodating a large number of devices. Two sets of springs B B are shown mounted on this base, the base being provided with raised side portions or strips 1 and c at its rear and front edges, respectively, and the springs B B being extended through and secured in the rear elevated strip 1. The front elevated strip 0 is provided with cylindrical channels or bores 0, which form plng-sockcts. The base or block C is provided with posts 2 3, which are adapted to make connection with the contact-strips B B. The rear elevated strip is provided with contact-posts 4 5 and the front elevated portion 0 with screws 6 7 and pins or posts a a. Plugs A A fit in the sockets or bores c 0, each plug conveniently consisting of a conducting portion a and an insulating portion (0 having a shoulder a. When either plug is in position in its socket,

its conducting portion a fits in between and makes physical contact with the line conducting-strips B B. Springs 1) D are attached to the rear ends of the plugs A A and are also connected to the raised ends of spring-supports E E, which are secured to the base or block C. Heat-coil devices F F are mounted in eyes H H, secured to the insulating portions of the plugs A A. Connecting strings or loops G G extend from the heatcoils F F and engage the posts a a. Each heat-coil device F consists of a body or mass of wax in which is confined a coil of line wire, and the ends '0' of this coil of wire extend out and are engaged by the screws 6 7, the ends of the loops G G being also embedded in the body or mass of wax. Conducting-wires I I connect the posts A I with the screws 6 6, the screws 7 7 with the contacts B B, and the contact-strips B B with the posts 5 5 and extend thence to the line and instrument to be protected.

The device in normal condition is as shown in Figs. 1 and 2, in which the springs D I) tend to withdraw the plugs A A from their sockets, but are prevented from so doing by the heat-coil devices F F, engaging the eyes H H, and the loops G G, engaging the posts a a, in which way the plugs are normally held in engagement with the contact-strips B B and the circuits thereby maintained closed. When an unduly-strong current traverses the circuits, or either of them, the heat-coil devices, or one of them, operate by the heating of their confined coils of line wire, so as to permit the wax to become fused or melted and the springs ID I) to separate the eyes H H from such masses of wax. The result is that the plugs, or one of them, are withdrawn from their sockets, and thereby their conducting ends a a are separated from the contact-strips B B, and the circuits are opened. To restore the device to operative condition, a new heat-coil or excess-current-operated device, consisting of the body or mass of wax, with the embedded heat coil and loop, is substituted for the former one, and the ends of the new coil are connected with the screws 6 7.

In the arrangement shown in Fig. 3 a simple fuse-wire 2' is substituted in place of the excesscurrent-operated device above set forth and shown in Figs. 1 and 2. Other than this the device is the same. The operation of this device is substantially the same,

the plug being held against withdrawal by the fuse and permitted to be withdrawn by the fusion or softening of this fuse-wire.

It will be understood that changes and modifications can be made without departing from the spirit of my invention.

What I claim is- 1. The combination with a base provided with a socket, of a plug adapted to litinto said socket, means tending to eject the plug, and an excess-current-operated device holding the plug normally against ejectment, substantially as described.

2. The combination with a post provided with a socket, of line-springs adapted to make contact with the plug when the same is inserted into the socket, spring means tending to withdraw the plug from its socket, and an excess-current-operated device holding the plug normally in the socket, substantially as described.

3. The combination with a base provided with a socket and plug, of line-springs B, B adapted to make contact with the plug, and an excess-current-operated device associated with the plug and controlling the removal thereof from the socket, substantially as described.

4. The combination with a base provided with a plugsocket,of line-springs RB adapted to make contact with the plug when the same isin its socket, spring means tending to withdraw the plug from its socket, and an excess-current-operated device holding the plug normally in its socket, substantially as described.

5. The combination with a base provided with a socket, a plug adapted to fit in said socket, spring means on the base for connecting with the end of the plug when the same is inserted in its socket, and an excess-currentoperated device associated with the plug and holding the same against the pull of said spring means, substantially as described.

6. A thermal cut-out for electric circuits,

comprising a sliding plug for opening and closing the circuit, a guide for the sliding plug, contacts opposite one end of the guide; a spring opposite the other end of the guide and normally under tension, and serving when released as a means for automatically throwing the plug forward and away from the contacts, and means for releasing the spring, involving a section of circuit-conductor which upon the development of heat therein as the result of an unduly-strong current, either fuses and breaks, or causes the fusion of a body of fusible materialassociated therewith, substantially as set forth.

7. A thermal cut-out, con'iprising a sliding plug for opening and closing the circuit, a body of fusible material held upon the plug, a hook or loop partially embedded in the body of fusible material and arranged for engaging a catch upon a fixed base when the plug is in circuit, a section of circuit-conductor held upon a fixed base and partially embedded in the body of fusible material, and a spring connected with the plug and under tension when the plug is held in circuit, substantially as set forth.

8. The combination and arrangement, in a thermal cut-out device, of the contacts, the sliding conducting-plug normally between and in engagement with said contacts, a guide for the plug, positioned opposite the space between the contacts, the body of fusible material retained by a holder upon the plug, the hook or loop partially embedded in the body of fusible material, and engaging a catch upon a fixed base, the wire 2 partially embedded in the body of fusible material and attached to a fixed base, and the coil-spring connecting one end of the plug with an arm on a fixed base, substantially as described.

CHARLES A. ROLFE.

Vitnessesz A. F. DURAND, L. M. STONE. 

